Malicious PDF — malware analysis report

Static analysis result for SHA-256 cf6aec26ce97b422…

MALICIOUS

PDF

75.7 KB Created: 2021-04-17 10:19:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-26
MD5: d1d804ac3bf958e81a49295c6153ae6f SHA-1: cab504d85d0a1efc1b73dbf699c61b24b9d5b67d SHA-256: cf6aec26ce97b4221700f2b9006a0d5ff1535845210071516322184aa2a3d2ce
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The ML classifier and ClamAV detection strongly indicate maliciousness. The PDF contains numerous embedded URLs, many pointing to seemingly benign academic or organizational sites, but the heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' suggests these are used to obscure malicious links. The document body, though heavily obfuscated, contains references to 'wkhtmltopdf' and 'Qt', indicating it was likely generated by a tool. The presence of embedded URLs and the overall structure point towards a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9978

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL https://www.uts.cw/sites/default/files/webform/89737617204.pdf In PDF document text
    • http://www.friendlycc.com/sites/default/files/webform/74296331991.pdfIn PDF document text
    • https://www.viachristi.org/sites/default/files/webform/89070061484.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/32041770382.pdfIn PDF document text
    • https://www.osgeurope.com/sites/osg-corporate.dev/files/webform/14219433733.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.daltonmaag.com/In PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/fzgW7-mxBc0/uplcv?utm_term=irregular+and+regular+verb+listPDF link annotation
    • https://minorsoncampus.princeton.edu/system/files/webform/97035559296.pdfIn PDF document text
    • https://drones.princeton.edu/system/files/webform/61493424170.pdfIn PDF document text
    • https://campusrec.princeton.edu/system/files/webform/febapaxugodikuzakepob.pdfIn PDF document text
    • https://minorsoncampus.princeton.edu/system/files/webform/wetesagepe.pdfIn PDF document text
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000dfe6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDFE6 4904 bytes
SHA-256: 3f19bfa0e61d10abf39d1e3e50f1e6eb1db8b621f98540c5442c948d0ba8532a
font_01_sfnt_off0000f092.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF092 10432 bytes
SHA-256: bf783c2dc35c5f2510a84fe0697d1e966e3eef071de1e526b9b12fafc20ca97e
font_02_sfnt_off00011442.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11442 4324 bytes
SHA-256: 05d2457133b820fa77aa358e30e9acfbad3f04c46ced9a37296d9311117db176

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